Triple Axis Compass Sensor for mailbox?

Cliff Karlsson

Yes, a magnet-switch would probably work. But my main concern regarding the magnet-switch is that I sometimes receives rather large parcels witch are jammed down the mailbox and would possible break of any magnet-switch that are placed inside the mailbox. The lid is where any sensor would be most protected. I might go with the simple magnet switch method to try out the durability but I would like to know if there are any options.

Would the Triple Axis Accelerometer from the mysensors-shop link work with just waking up when lid is moved? Or could a PIR be able to use interrupt to wake up?

hek

I've mounted mine like this:

It's been sitting there for almost 3 years now.

Cliff Karlsson

My mailbox kid of looks like this:

Yveaux

@Cliff-Karlsson Could you post a real picture and draw where you would mount the compass sensor?
I expect the compass sensor is even more fragile than a door sensor and wont last very long...

Cliff Karlsson

@Yveaux said:

@Cliff-Karlsson Could you post a real picture and draw where you would mount the compass sensor?

It looks similar to this one and I would place everything inside a sealed plastic box glued to the top of the lid if that kind of sensor is a good idea battery-wise.

0_1461518850285_brevlåda.jpg

Yveaux

@Cliff-Karlsson I would expect you can find a place to firmly glue a small magnet (neodimium) to the bottom part (the one with 'POST' on it) that will survive even your most extreme AliExpress deliveries ;-)

Cliff Karlsson

Ahhh, that idea did not strike me that I could use a different neodymium magnet instead of the one that was shipped with the magnet-switch. I guess that I just can place a strong magnet on the side of the mailbox. No glue needed as I almost break my nails of when trying to get those 20x3(?)mm magnets of my refridgerator

Yveaux

@Cliff-Karlsson They come in all sizes. The door-sensor part without wires contains just a magnet, nothing more.

Cliff Karlsson

I want to try to build simple sensor using the door/window/button sketch:


#include <MySensor.h>
#include <SPI.h>
#include <Bounce2.h>

#define CHILD_ID 3
#define BUTTON_PIN  3  // Arduino Digital I/O pin for button/reed switch

MySensor gw;
Bounce debouncer = Bounce(); 
int oldValue=-1;

// Change to V_LIGHT if you use S_LIGHT in presentation below
MyMessage msg(CHILD_ID,V_TRIPPED);

void setup()  
{  
  gw.begin();

 // Setup the button
  pinMode(BUTTON_PIN,INPUT);
  // Activate internal pull-up
  digitalWrite(BUTTON_PIN,HIGH);
  
  // After setting up the button, setup debouncer
  debouncer.attach(BUTTON_PIN);
  debouncer.interval(5);
  
  // Register binary input sensor to gw (they will be created as child devices)
  // You can use S_DOOR, S_MOTION or S_LIGHT here depending on your usage. 
  // If S_LIGHT is used, remember to update variable type you send in. See "msg" above.
  gw.present(CHILD_ID, S_DOOR);  
}


//  Check if digital input has changed and send in new value
void loop() 
{
  debouncer.update();
  // Get the update value
  int value = debouncer.read();
 
  if (value != oldValue) {
     // Send in the new value
     gw.send(msg.set(value==HIGH ? 1 : 0));
     oldValue = value;
  }
}

And also add the battery masuring from :

#include <SPI.h>
#include <MySensor.h>

#define round(x) ((x)>=0?(long)((x)+0.5):(long)((x)-0.5))
#define N_ELEMENTS(array) (sizeof(array)/sizeof((array)[0]))

#define CHILD_ID_MOISTURE 0
#define CHILD_ID_BATTERY 1
#define SLEEP_TIME 1800000 // Sleep time between reads (in milliseconds)
#define THRESHOLD 1.1 // Only make a new reading with reverse polarity if the change is larger than 10%.
#define STABILIZATION_TIME 1000 // Let the sensor stabilize before reading
#define BATTERY_FULL 3143 // 2xAA usually give 3.143V when full
#define BATTERY_ZERO 2340 // 2.34V limit for 328p at 8MHz. 1.9V, limit for nrf24l01 without step-up. 2.8V limit for Atmega328 with default BOD settings.
const int SENSOR_ANALOG_PINS[] = {A0, A1}; // Sensor is connected to these two pins. Avoid A3 if using ATSHA204. A6 and A7 cannot be used because they don't have pullups.

MySensor gw;
MyMessage msg(CHILD_ID_MOISTURE, V_HUM);
MyMessage voltage_msg(CHILD_ID_BATTERY, V_VOLTAGE);
long oldvoltage = 0;
byte direction = 0;
int oldMoistureLevel = -1;

void setup()
{
  gw.begin();

  gw.sendSketchInfo("Plant moisture w bat", "1.5");

  gw.present(CHILD_ID_MOISTURE, S_HUM);
  delay(250);
  gw.present(CHILD_ID_BATTERY, S_CUSTOM);
  for (int i = 0; i < N_ELEMENTS(SENSOR_ANALOG_PINS); i++) {
    pinMode(SENSOR_ANALOG_PINS[i], OUTPUT);
    digitalWrite(SENSOR_ANALOG_PINS[i], LOW);
  }
}

void loop()
{
  int moistureLevel = readMoisture();

  // Send rolling average of 2 samples to get rid of the "ripple" produced by different resistance in the internal pull-up resistors
  // See http://forum.mysensors.org/topic/2147/office-plant-monitoring/55 for more information
  if (oldMoistureLevel == -1) { // First reading, save current value as old
    oldMoistureLevel = moistureLevel;
  }
  if (moistureLevel > (oldMoistureLevel * THRESHOLD) || moistureLevel < (oldMoistureLevel / THRESHOLD)) {
    // The change was large, so it was probably not caused by the difference in internal pull-ups.
    // Measure again, this time with reversed polarity.
    moistureLevel = readMoisture();
  }
  gw.send(msg.set((moistureLevel + oldMoistureLevel) / 2.0 / 10.23, 1));
  oldMoistureLevel = moistureLevel;
  long voltage = readVcc();
  if (oldvoltage != voltage) { // Only send battery information if voltage has changed, to conserve battery.
    gw.send(voltage_msg.set(voltage / 1000.0, 3)); // redVcc returns millivolts. Set wants volts and how many decimals (3 in our case)
    gw.sendBatteryLevel(round((voltage - BATTERY_ZERO) * 100.0 / (BATTERY_FULL - BATTERY_ZERO)));
    oldvoltage = voltage;
  }
  gw.sleep(SLEEP_TIME);
}

int readMoisture() {
  pinMode(SENSOR_ANALOG_PINS[direction], INPUT_PULLUP); // Power on the sensor
  analogRead(SENSOR_ANALOG_PINS[direction]);// Read once to let the ADC capacitor start charging
  gw.sleep(STABILIZATION_TIME);
  int moistureLevel = (1023 - analogRead(SENSOR_ANALOG_PINS[direction]));

  // Turn off the sensor to conserve battery and minimize corrosion
  pinMode(SENSOR_ANALOG_PINS[direction], OUTPUT);
  digitalWrite(SENSOR_ANALOG_PINS[direction], LOW);

  direction = (direction + 1) % 2; // Make direction alternate between 0 and 1 to reverse polarity which reduces corrosion
  return moistureLevel;
}

long readVcc() {
  // From http://provideyourown.com/2012/secret-arduino-voltmeter-measure-battery-voltage/
  // Read 1.1V reference against AVcc
  // set the reference to Vcc and the measurement to the internal 1.1V reference
#if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
  ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#elif defined (__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
  ADMUX = _BV(MUX5) | _BV(MUX0);
#elif defined (__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
  ADMUX = _BV(MUX3) | _BV(MUX2);
#else
  ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#endif

  delay(2); // Wait for Vref to settle
  ADCSRA |= _BV(ADSC); // Start conversion
  while (bit_is_set(ADCSRA, ADSC)); // measuring

  uint8_t low  = ADCL; // must read ADCL first - it then locks ADCH
  uint8_t high = ADCH; // unlocks both

  long result = (high << 8) | low;

  result = 1125300L / result; // Calculate Vcc (in mV); 1125300 = 1.1*1023*1000
  return result; // Vcc in millivolts
}

Do I "just" add these parts to the first sketch to have battery measuring working:

#define CHILD_ID_BATTERY 1

#define BATTERY_FULL 3143 // 2xAA usually give 3.143V when full
#define BATTERY_ZERO 2340

MyMessage voltage_msg(CHILD_ID_BATTERY, V_VOLTAGE);
long oldvoltage = 0;

gw.present(CHILD_ID_BATTERY, S_CUSTOM);

long voltage = readVcc();
  if (oldvoltage != voltage) { // Only send battery information if voltage has changed, to conserve battery.
    gw.send(voltage_msg.set(voltage / 1000.0, 3)); // redVcc returns millivolts. Set wants volts and how many decimals (3 in our case)
    gw.sendBatteryLevel(round((voltage - BATTERY_ZERO) * 100.0 / (BATTERY_FULL - BATTERY_ZERO)));
    oldvoltage = voltage;
	
	
long readVcc() {
  // From http://provideyourown.com/2012/secret-arduino-voltmeter-measure-battery-voltage/
  // Read 1.1V reference against AVcc
  // set the reference to Vcc and the measurement to the internal 1.1V reference
#if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
  ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#elif defined (__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
  ADMUX = _BV(MUX5) | _BV(MUX0);
#elif defined (__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
  ADMUX = _BV(MUX3) | _BV(MUX2);
#else
  ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#endif

  delay(2); // Wait for Vref to settle
  ADCSRA |= _BV(ADSC); // Start conversion
  while (bit_is_set(ADCSRA, ADSC)); // measuring

  uint8_t low  = ADCL; // must read ADCL first - it then locks ADCH
  uint8_t high = ADCH; // unlocks both

  long result = (high << 8) | low;

  result = 1125300L / result; // Calculate Vcc (in mV); 1125300 = 1.1*1023*1000
  return result; // Vcc in millivolts
}

Cliff Karlsson

I used the BinarySwitchSleepSensor sketch and tried adding the battery measuring info. Does this look ok If I only want the sensor to sleep until the magnetswitch attached to PIN 2 is opened and every 6h it reports battery?

// Enable debug prints to serial monitor
#define MY_DEBUG 
#define SLEEP_TIME 21600000 // Sleep time between reads (in milliseconds)
// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

#include <SPI.h>
#include <MySensor.h>

#define SKETCH_NAME "Mailbox +Battery"
#define SKETCH_MAJOR_VER "1"
#define SKETCH_MINOR_VER "0"

#define PRIMARY_CHILD_ID 3
#define CHILD_ID_BATTERY 1

#define BATTERY_FULL 3143 // 2xAA usually give 3.143V when full
#define BATTERY_ZERO 2340

#define PRIMARY_BUTTON_PIN 2   // Arduino Digital I/O pin for button/reed switch




// Change to V_LIGHT if you use S_LIGHT in presentation below
MyMessage msg(PRIMARY_CHILD_ID, V_TRIPPED);
MyMessage voltage_msg(CHILD_ID_BATTERY, V_VOLTAGE);
long oldvoltage = 0;

void setup()  
{  
  // Setup the buttons
  pinMode(PRIMARY_BUTTON_PIN, INPUT);
 

  // Activate internal pull-ups
  digitalWrite(PRIMARY_BUTTON_PIN, HIGH);

}

void presentation() {
  // Send the sketch version information to the gateway and Controller
  sendSketchInfo(SKETCH_NAME, SKETCH_MAJOR_VER "." SKETCH_MINOR_VER);

  // Register binary input sensor to sensor_node (they will be created as child devices)
  // You can use S_DOOR, S_MOTION or S_LIGHT here depending on your usage. 
  // If S_LIGHT is used, remember to update variable type you send in. See "msg" above.
  present(PRIMARY_CHILD_ID, S_DOOR);  
  delay(250);
  present(CHILD_ID_BATTERY, S_CUSTOM); 
}

// Loop will iterate on changes on the BUTTON_PINs
void loop() 
{
  uint8_t value;
  static uint8_t sentValue=2;

  // Short delay to allow buttons to properly settle
  sleep(5);
  
  value = digitalRead(PRIMARY_BUTTON_PIN);
  
  if (value != sentValue) {
     // Value has changed from last transmission, send the updated value
     send(msg.set(value==HIGH ? 1 : 0));
     sentValue = value;
  }
long voltage = readVcc();
  if (oldvoltage != voltage) { // Only send battery information if voltage has changed, to conserve battery.
    send(voltage_msg.set(voltage / 1000.0, 3)); // redVcc returns millivolts. Set wants volts and how many decimals (3 in our case)
    sendBatteryLevel(round((voltage - BATTERY_ZERO) * 100.0 / (BATTERY_FULL - BATTERY_ZERO)));
    oldvoltage = voltage;
  }
  

  // Sleep until something happens with the sensor
  sleep(PRIMARY_BUTTON_PIN-2, CHANGE, SLEEP_TIME);
} 

long readVcc() {
  // From http://provideyourown.com/2012/secret-arduino-voltmeter-measure-battery-voltage/
  // Read 1.1V reference against AVcc
  // set the reference to Vcc and the measurement to the internal 1.1V reference
#if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
  ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#elif defined (__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
  ADMUX = _BV(MUX5) | _BV(MUX0);
#elif defined (__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
  ADMUX = _BV(MUX3) | _BV(MUX2);
#else
  ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#endif

  delay(2); // Wait for Vref to settle
  ADCSRA |= _BV(ADSC); // Start conversion
  while (bit_is_set(ADCSRA, ADSC)); // measuring

  uint8_t low  = ADCL; // must read ADCL first - it then locks ADCH
  uint8_t high = ADCH; // unlocks both

  long result = (high << 8) | low;

  result = 1125300L / result; // Calculate Vcc (in mV); 1125300 = 1.1*1023*1000
  return result; // Vcc in millivolts
}

Triple Axis Compass Sensor for mailbox?

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